diff --git a/js/geo-gyroid.js b/js/geo-gyroid.js
new file mode 100644
index 00000000..b6c8bf4a
--- /dev/null
+++ b/js/geo-gyroid.js
@@ -0,0 +1,156 @@
+/** Copyright 2014-2018 Stewart Allen -- All Rights Reserved */
+
+"use strict";
+
+var gs_base_gyroid = exports;
+
+(function() {
+    if (!self.base) self.base = {};
+    if (self.base.gyroid) return;
+
+    var base = self.base;
+
+    let PI2 = Math.PI * 2;
+
+    /**
+     * @param off {number} z offset value from 0-1
+     * @param res {number} resolution (pixels/slices per side)
+     */
+    function slice(off, res) {
+        let rez = parseInt(res || 200);
+        let inc = PI2 / rez;
+        let z = PI2 * off;
+
+        let edge = [];
+        let vals = [];
+        let points = 0;
+        let points_lr = 0;
+        let points_td = 0;
+        for (let x=0; x<PI2; x += inc) {
+            let vrow = []; // raw values row
+            let erow = []; // edge values row
+            edge.push(erow);
+            vals.push(vrow);
+            for (let y=0; y<PI2; y += inc) {
+                erow.push(0);
+                vrow.push(
+                    Math.sin(x) * Math.cos(y) +
+                    Math.sin(y) * Math.cos(z) +
+                    Math.sin(z) * Math.cos(x)
+                );
+            }
+        }
+
+        // left-right threshold search (red)
+        vals.forEach((vrow, y) => {
+            let erow = edge[y];
+            let lval = vrow[vrow.length - 1];
+            vrow.forEach((val, x) => {
+                if (lval <= 0 && val >= 0) {
+                    erow[x] = 1;
+                    points++;
+                    points_lr++;
+                }
+                lval = val;
+            })
+        });
+
+        // top-down threshold search (green)
+        for (let x=0; x<rez; x++) {
+            let lval = vals[vals.length-1][x];
+            for (let y=0; y<rez; y++) {
+                let val = vals[y][x];
+                if (lval <= 0 && val >= 0) {
+                    if (edge[y][x]) {
+                        edge[y][x] = 3;
+                    } else {
+                        edge[y][x] = 2;
+                        points++
+                    }
+                    points_td++;
+                }
+                lval = val;
+            }
+        }
+
+        // deterime prevailing direction for chaining
+        let dir = points_td > points_lr ? 'lr' : 'td';
+
+        // create sparse representation
+        let sparse = [];
+        let center = rez / 2;
+        edge.forEach((row,y) => {
+            row.forEach((val,x) => {
+                if (val) {
+                    let dx = Math.abs(x - center);
+                    let dy = Math.abs(y - center);
+                    sparse.push({x: x/rez, y: y/rez, val, dist: Math.max(dx,dy)});
+                }
+            });
+        });
+        sparse.sort((a,b) => {
+            return b.dist - a.dist;
+        });
+
+        // join sparse points array by closest distance
+        let polys = [];
+        let chain;
+        let added;
+        let cleared = 0;
+        let maxdist = 0.05;
+
+        do {
+            chain = null;
+            for (let i=0; i<sparse.length; i++) {
+                if (sparse[i]) {
+                    chain = [ sparse[i] ];
+                    polys.push(chain);
+                    sparse[i] = null;
+                    cleared++;
+                    break;
+                }
+            }
+            do {
+                added = false;
+                let target = chain[chain.length - 1];
+                let cl_elm = null;
+                let cl_idx = null;
+                let cl_dst = Infinity;
+                for (let i=0; i<sparse.length; i++) {
+                    let test_el = sparse[i];
+                    if (test_el) {
+                        let dst = dist(target, test_el, dir);
+                        if (cl_idx === null || dst < cl_dst) {
+                            cl_idx = i;
+                            cl_elm = test_el;
+                            cl_dst = dst;
+                        }
+                    }
+                }
+                if (cl_elm) {
+                    if (cl_dst > maxdist) {
+                        break;
+                    }
+                    sparse[cl_idx] = null;
+                    cleared++;
+                    chain.push(cl_elm);
+                    added = true;
+                }
+            } while (added);
+        } while (cleared < sparse.length);
+
+        return {edge, points, dir, polys};
+    }
+
+    function dist(a, b, dir) {
+        let dx = a.x - b.x;
+        let dy = a.y - b.y;
+        // bias distance by prevailing direction of discovery to join stragglers
+        if (dir === 'lr') dx = dx / 2;
+        if (dir === 'td') dy = dy / 2;
+        return Math.sqrt(dx * dx + dy * dy);
+    }
+
+    base.gyroid = { slice };
+
+})();
diff --git a/js/kiri-driver-fdm.js b/js/kiri-driver-fdm.js
index 338a0873..8f9b8512 100644
--- a/js/kiri-driver-fdm.js
+++ b/js/kiri-driver-fdm.js
@@ -65,7 +65,7 @@ var gs_kiri_fdm = exports;
 
         SLICER.sliceWidget(widget, {
             height: spro.sliceHeight,
-            minHeight: spro.sliceMinHeight,
+            minHeight: spro.sliceHeight > spro.sliceMinHeight ? spro.sliceMinHeight : 0,
             firstHeight: spro.firstSliceHeight,
             view: view
         }, onSliceDone, onSliceUpdate);
@@ -149,7 +149,13 @@ var gs_kiri_fdm = exports;
             // sparse layers only present when non-vase mose and sparse % > 0
             if (!spro.sliceVase && spro.sliceFillSparse > 0.0) {
                 forSlices(0.8, 1.0, function(slice) {
-                    slice.doSparseLayerFill(fillSpacing, spro.sliceFillSparse, widget.getBoundingBox());
+                    slice.doSparseLayerFill({
+                        spacing: fillSpacing,
+                        density: spro.sliceFillSparse,
+                        bounds: widget.getBoundingBox(),
+                        height: spro.sliceHeight,
+                        type: spro.sliceFillGyroid ? 'gyroid' : 'hex'
+                    });
                 }, "infill");
             }
 
diff --git a/js/kiri-slice.js b/js/kiri-slice.js
index 99f41c42..d7db77a7 100644
--- a/js/kiri-slice.js
+++ b/js/kiri-slice.js
@@ -593,14 +593,16 @@ var gs_kiri_slice = exports;
     /**
      * Take output from pluggable sparse infill algorithm and clip to
      * the bounds of the top polygons and their inner solid areas.
-     *
-     * @param {number} spacing space between fill lines
-     * @param {number} percent infill 0.0 - 1.0
-     * @param {Object} bounds -- TODO calc w/out mesh so it can run in a worker
      */
-    PRO.doSparseLayerFill = function(spacing, percent, bounds) {
+    PRO.doSparseLayerFill = function(options) {
+        let spacing = options.spacing,  // spacing space between fill lines
+            density = options.density,  // density of infill 0.0 - 1.0
+            bounds = options.bounds,    // bounding box of widget
+            height = options.height,    // z layer height
+            type = options.type || 'hex';
+
         this.isSparseFill = false;
-        if (this.tops.length === 0 || percent === 0.0 || this.isSolidFill) return;
+        if (this.tops.length === 0 || density === 0.0 || this.isSolidFill) return;
 
         var scope = this,
             tops = scope.tops,
@@ -619,8 +621,9 @@ var gs_kiri_slice = exports;
                 bounds: function() { return bounds },
                 zIndex: function() { return scope.index },
                 zValue: function() { return scope.z },
-                density: function() { return percent },
+                zHeight: function() { return height },
                 offset: function() { return spacing },
+                density: function() { return density },
                 emit: function(x,y) { line.push(newPoint(x,y,scope.z)) },
                 newline: function() {
                     if (line.length > 0) {
@@ -631,8 +634,13 @@ var gs_kiri_slice = exports;
             };
 
         scope.isSparseFill = true;
-        // this is pluggable
-        sparseFillHex(target, true);
+
+        // use specified fill type
+        switch (type) {
+            case 'hex': sparseFillHex(target, true); break;
+            case 'gyroid': sparseFillGyroid(target); break;
+        }
+
         // force emit of last line
         target.newline();
 
@@ -1280,6 +1288,32 @@ var gs_kiri_slice = exports;
         }
     }
 
+    function sparseFillGyroid(target) {
+        let bounds = target.bounds();
+        let height = target.zHeight();
+        let span_x = bounds.max.x - bounds.min.x;
+        let span_y = bounds.max.y - bounds.min.y;
+        let density = target.density();
+        let tile = 1 + (1 - density) * 15;
+        let tile_x = span_x / tile;
+        let tile_y = span_y / tile;
+        let tile_z = 1 / tile;
+        let gyroid = BASE.gyroid.slice(target.zValue() * tile_z, (1 - density) * 500);
+
+        gyroid.polys.forEach(poly => {
+            for (let tx=0; tx<=tile_x; tx++) {
+                for (let ty=0; ty<=tile_y; ty++) {
+                    target.newline();
+                    let bx = tx * tile + bounds.min.x;
+                    let by = ty * tile + bounds.min.y;
+                    poly.forEach(point => {
+                        target.emit(bx + point.x * tile, by + point.y * tile);
+                    });
+                }
+            }
+        });
+    }
+
     function newTop(poly) {
         return new Top(poly);
     }
diff --git a/js/kiri-work.js b/js/kiri-work.js
index f54f9664..15656066 100644
--- a/js/kiri-work.js
+++ b/js/kiri-work.js
@@ -154,7 +154,7 @@ if (self.window) {
             [
                 "license","ext-n3d","ext-clip","add-array",
                 "add-three","geo","geo-point","geo-debug","geo-bounds",
-                "geo-line","geo-slope","geo-polygon","geo-polygons",
+                "geo-line","geo-slope","geo-polygon","geo-polygons", "geo-gyroid",
                 "kiri-slice","kiri-slicer","kiri-driver-fdm","kiri-driver-cam",
                 "kiri-driver-laser","kiri-widget","kiri-pack","kiri-print","kiri-codec"
             ].forEach(function(scr) {
diff --git a/js/kiri.js b/js/kiri.js
index 0c9a8653..e49977ed 100644
--- a/js/kiri.js
+++ b/js/kiri.js
@@ -60,6 +60,7 @@ self.kiri.license = exports.LICENSE;
                     sliceFillOverlap: 1,
                     sliceFillSpacing: 1,
                     sliceFillSparse: 1,
+                    sliceFillGyroid: 1,
                     sliceSupportEnable: 1,
                     sliceSupportDensity: 1,
                     sliceSupportOffset: 1,
@@ -270,6 +271,7 @@ self.kiri.license = exports.LICENSE;
                 sliceFillOverlap: 0.3,
                 sliceFillSpacing: 1.0,
                 sliceFillSparse: 0.5,
+                sliceFillGyroid: false,
 
                 sliceSupportEnable: false,
                 sliceSupportDensity: 0.25,
@@ -2462,6 +2464,7 @@ self.kiri.license = exports.LICENSE;
             sliceFillSpacing: UC.newInput("fill spacing", {title:"for solid fill areas\nas a percentage of nozzle width\n< 1.0 causes fill overlap\nrecommended 0.85 - 1.0", convert:UC.toFloat, bound:UC.bound(0.0,2.0), modes:FDM}),
             sliceFillAngle: UC.newInput("fill angle", {title:"base angle in degrees", convert:UC.toFloat, modes:FDM}),
             sliceFillSparse: UC.newInput("fill ratio", {title:"for infill areas\n0.0 - 1.0", convert:UC.toFloat, bound:UC.bound(0.0,1.0), modes:FDM}),
+            sliceFillGyroid: UC.newBoolean("fill gyroid", onBooleanClick, {modes:FDM}),
             sliceSolidMinArea: UC.newInput("solid area", {title:"minimum area (mm^2)\nrequired to keep solid\nmust be > 0.1", convert:UC.toFloat, modes:FDM}),
             sliceSolidLayers: UC.newInput("solid layers", {title:"flat area fill projections\nbased on layer deltas", convert:UC.toInt, modes:FDM}),
             sliceBottomLayers: UC.newInput("base layers", {title:"bottom solid layer count", convert:UC.toInt, modes:FDM}),
diff --git a/js/license.js b/js/license.js
index 770960cb..87c3b76b 100644
--- a/js/license.js
+++ b/js/license.js
@@ -1,7 +1,7 @@
 var exports = {
     COPYRIGHT:"Copyright (C) 2014-2018 Stewart Allen <sa@grid.space> - All Rights Reserved",
     LICENSE:"See the license.md file included with the source distribution",
-    VERSION:"1.2.5a"
+    VERSION:"1.2.6"
 };
 if (!module) var module = {};
 module.exports = exports;
diff --git a/js/web-server.js b/js/web-server.js
index 1fd9c1e0..352348d6 100644
--- a/js/web-server.js
+++ b/js/web-server.js
@@ -743,6 +743,7 @@ var ver = require('../js/license.js'),
             "geo-bounds",
             "geo-polygon",
             "geo-polygons",
+            "geo-gyroid",
             "moto-kv",
             "moto-ajax",
             "moto-ctrl",
@@ -795,6 +796,7 @@ var ver = require('../js/license.js'),
             "geo-bounds",
             "geo-polygon",
             "geo-polygons",
+            "geo-gyroid",
             "kiri-slice",
             "kiri-slicer",
             "kiri-driver-fdm",